/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.transformation.dag.udf;

import org.apache.iotdb.commons.udf.service.UDFManagementService;
import org.apache.iotdb.commons.udf.utils.UDFDataTypeTransformer;
import org.apache.iotdb.db.exception.sql.SemanticException;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.udf.api.UDTF;
import org.apache.iotdb.udf.api.customizer.config.UDTFConfigurations;
import org.apache.iotdb.udf.api.customizer.parameter.UDFParameterValidator;
import org.apache.iotdb.udf.api.customizer.parameter.UDFParameters;
import org.apache.iotdb.udf.api.customizer.strategy.AccessStrategy;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.time.ZoneId;
import java.util.List;
import java.util.Map;

public class UDTFInformationInferrer {

    private static final Logger LOGGER = LoggerFactory.getLogger(UDTFInformationInferrer.class);

    protected final String functionName;

    public UDTFInformationInferrer(String functionName) {
        this.functionName = functionName;
    }

    public TSDataType inferOutputType(
            List<String> childExpressions,
            List<TSDataType> childExpressionDataTypes,
            Map<String, String> attributes) {
        try {
            return UDFDataTypeTransformer.transformToTsDataType(
                    reflectAndGetConfigurations(childExpressions, childExpressionDataTypes, attributes)
                            .getOutputDataType());
        } catch (Exception e) {
            LOGGER.warn("Error occurred during inferring UDF data type", e);
            throw new SemanticException(
                    String.format("Error occurred during inferring UDF data type: %s", System.lineSeparator())
                            + e);
        }
    }

    public AccessStrategy getAccessStrategy(
            List<String> childExpressions,
            List<TSDataType> childExpressionDataTypes,
            Map<String, String> attributes) {
        try {

            return reflectAndGetConfigurations(childExpressions, childExpressionDataTypes, attributes)
                    .getAccessStrategy();
        } catch (Exception e) {
            LOGGER.warn("Error occurred during getting UDF access strategy", e);
            throw new SemanticException(
                    String.format(
                            "Error occurred during getting UDF access strategy: %s", System.lineSeparator())
                            + e);
        }
    }

    private UDTFConfigurations reflectAndGetConfigurations(
            List<String> childExpressions,
            List<TSDataType> childExpressionDataTypes,
            Map<String, String> attributes)
            throws Exception {
        UDTF udtf = (UDTF) UDFManagementService.getInstance().reflect(functionName);

        UDFParameters parameters =
                new UDFParameters(
                        childExpressions,
                        UDFDataTypeTransformer.transformToUDFDataTypeList(childExpressionDataTypes),
                        attributes);
        udtf.validate(new UDFParameterValidator(parameters));

        // use ZoneId.systemDefault() because UDF's data type is ZoneId independent
        UDTFConfigurations configurations = new UDTFConfigurations(ZoneId.systemDefault());
        udtf.beforeStart(parameters, configurations);
        udtf.beforeDestroy();
        return configurations;
    }
}
